1. Field of the Invention
The present invention relates to manufacturing methods of an airtight container and an image display apparatus. In particular, the present invention relates to manufacturing methods of an airtight container and an image display apparatus, each of which includes a non-evaporable type getter.
2. Description of the Related Art
There is known a planar type image display apparatus, which irradiates an electron beam emitted from electron emitting elements provided on a planar substrate onto a phosphor on an opposite substrate, to allow the phosphor to emit light for displaying an image. For such an image display apparatus, it is necessary to hold, at a high vacuum, an inside of an airtight container that includes therein the electron emitting elements and the phosphor. This is because, when gas is generated in the inside of the airtight container and a pressure thereof rises, the electron emitting elements are adversely affected to decrease an amount of electrons emitted therefrom though a magnitude of the adverse effect differs depending on a type of the gas.
In order to solve such a problem, a structure has been proposed, in which a getter is formed in the inside of the airtight container, and the gas generated therein is adsorbed to the getter.
Here, the getter includes an evaporable type getter and a non-evaporable type getter. There are types of the gas which are more likely to be adsorbed to the getter and those that are less likely to be adsorbed thereto. The evaporable type getter has an extremely high exhaust speed for water and oxygen, but has an extremely low exhaust speed for inert gas such as argon (Ar). Further, the non-evaporable type getter also has an extremely low exhaust speed for the inert gas such as Ar. In particular, a non-evaporable type getter deposited by a sputtering method using Ar contains Ar gas in an inside thereof, and emits the Ar gas after the airtight container is formed. Accordingly, a pressure of the Ar gas in the airtight container rises.
In this connection, Japanese Patent Application Laid-Open No. H07-296732 discloses a method of preheating the non-evaporable type getter, and thereby degassing a surface of the getter.
Further, Japanese Patent Application Laid-Open No. 2000-133136 discloses a method of irradiating the electron beam onto the non-evaporable type getter while exhausting the inside thereof by an exhaust pipe, and thereby activating the getter.